Either the bug is fixed or there is a subtle difference between our installations, but I do not get an error
I've reproduced the problem using a more recent ConTeXt: ConTeXt ver: 2009.06.04 22:20 MKII pdfTeXk, Version 3.1415926-1.40.9 The test files are in the attached zip file, which expands into a vadjust-problem/ directory. Then "texexec symmetry.tex" reproduces the problem for me. Here is the error message: ./symmetry.tex:920: You can't use `\vadjust' in internal vertical mode. <recently read> \vadjust \sidefloatoutput ... \parskip \zeropoint \vadjust {\penalty \minusone }\iffl... <argument> ...\fi \else \the \defaultstreamoutput \fi \firstoftwoarguments #1#2->#1 \dodonormaloutput ...lty \the \OTRcommand \output \outputmessage -{normal}\o... \invokeoutputroutine ...enalty }\dodonormaloutput \outputmessage -{trying}\o... ...